This story is going to be short there isn't much to it, but I'm not sure what I was seeing. This happened several times and they were all pretty much the same. So I'll describe just one of the times because I only remember (that's how much similar they all were), but I know it happened more than once.
I was in the kitchen, not sure why, I was probably eating lunch or something. Most of the time when I go in the kitchen I usually look out the windows (I'm a very curious person, so I always look out windows just to see what's going on outside). So I looked out the window and across the street I saw a pale face looking out the window of the middle apartment in the apartment building across the street. It disappeared after a bit. Every time it happened it was a pale blank face looking out the window but it was never in the same window. This only happened when no one was home in that building.
I knew the people who lived there at the time. I told them and they laughed and said they had never seen anything in the house, and there wasn't anything wrong with it. The only mysterious thing that happened to their apartment, they told me morning after it happened. It was that when they (3 kids/teens) where in their room which was upstairs in the back of the apartment, it was night and a snowball was thrown at there smaller window where the bedroom extends out a bit. When they looked there was no one and no footprints or anything.
How would you guys explain this, what was it, what was I seeing.